Some MTB shots from today, I tasked myself with going manual but battled with the sun and clouds all afternoon so not sure about them overall, there was another guy there using a flash but being an ex biker I'm not to fussed on a flash firing when I'm in mid flight but he said it was all about positioning and timing. I'd also have to brush up on my flash skills, I'm not to sure about shooting sport with a flash.

From the point of view of a crap photographer and arthritic sloth, I pretty much agree with what @ianganderton said before - dark backrounds and dark tops.
I also agree with what you say about being reluctant to use flash and I don't think that the weather helped you too much either.

Thanks Ian, That's pretty much what i was thinking and unfortunately most riders were in dark colours and Cwmcarn is a very green venue. If anybody can offer strobe advice in this situation that'd be great, I have an SB600.

_________________"I'm playing all the right notes but not necessarily in the right order" - Eric Morecambe________________________________________D7000 and too many lenses.

Once you've learnt and understood how to control the SB-600 remotely using the on board flash and menu, I'd pop outside in similar lighting conditions to practise with your gear on a stationary object at around the same distance you can get away with when photographing the cyclists. If you're SB-600 can produce enough power to illuminate the subject then you're good to go. Try using manual modes and TTL modes. The way the ambient light can be controlled can differ between manual and TTL - here's a good link:

So if CLS works in your outdoor scenario, you have two on board options for controlling your SB-600 - Full Manual or TTL

If the on board flash is overpowered by sunlight and doesn't trip the SB-600, the radio triggers will work in Full Manual mode only (unless you're got Pocket Wizard's new Flex system, which are pretty cool and expensive by the way!)

Thanks i'm going to give it a go but perhaps when the riders are not so vulnerable to an off what about shutter speed? I was shooting at around 1/1000 sometimes more with a high ISO but the strobe will only allow 1/250

_________________"I'm playing all the right notes but not necessarily in the right order" - Eric Morecambe________________________________________D7000 and too many lenses.

Look at the D7000 manual - you'll be able to set up high speed synch to shoot up to 1/8000th.

If you're shooting in TTL with the flash controlled off camera by the on board flash, dialling in -1EV should reduce the ambient and flash exposure. Then dialling in +1 Flash EV on top will cancel out the Flash underexposure, giving a bit of separation between the subject and background.

This is where Nikon TTL differs from Canon TTL - in Canon I think changing the exposure comp. doesn't effect the flash, whereas in Nikon it does.

Would shooting with a slower shutter speed, a flash and some panning movement not produce an effect where the background was blurred more and the subject frozen and so separating the subject from the background more.

These were taken by a magazine photographer and he used a remote flash held up high on a 'stick'. Definitely created some separation of the subject from the background

If I was biking and someone was taking photos with a flash I wouldnt be bothered as long as its not in my direct line of sight and blinding me. This is happening in daylight so its only adding a bit of light not providing ALL the light. The problems would occur in dark areas where a sudden flash would force your eyes to adjust and then not be able to see